In almost any scandal of the scale and complexity of the one engulfing News International, the UK press subsidiary of Rupert Murdoch's News Corporation, the investigation usually turns on two simple questions: Who knew what, and when?

Answering those questions will be at the heart of an investigation promised by the UK Parliament. Of particular concern to Mr. Murdoch is the position of his son and heir apparent James, who was running News International at a time when some of its newspapers are alleged to have been bribing policemen and illegally hacking into the cellphone messages of politicians, crime victims, and celebrities.

Tom Crone, News International's legal boss for a quarter of a century, left his job today. While there, he spent extensive time determining whether the contents of the salacious Sunday weekly News of the World (NotW) and its daily sister tabloid The Sun crossed the legal line. He would have "lawyered" many of the exclusives obtained through bribery or phone hacking at NotW, ordered closed by the elder Murdoch last week.

Whether he jumped or was pushed still isn't clear. But his role at the paper, particularly in a decision three years ago to pay large out-of-court settlements to two men whose phones were hacked into by the company's employees, is sure to be under scrutiny in the coming weeks and months.

Mr. Crone told Parliament in 2009 that he'd recommended and approved a $1 million settlement paid to Gordon Taylor, the head of the Professional Football Association, whose phone had been illegally hacked by NotW reporters. Colin Myler, then NotW editor, told Parliament that he, Crone, and James Murdoch collectively decided to make that payment. That hearing came after The Guardian newspaper broke the story of the paper's payments. Celebrity publicist Max Clifford also reportedly received a settlement of over $1 million.

That has raised tantalizing questions about how much James knew about the illegal practices at NotW – both during his time at News International and before. A reporter and a private investigator for the paper were jailed in 2007 for illegally hacking into cellphones. After that incident News International investigated practices there – led by Crone – and declared the matter an isolated incident.

But following the revelations of more abuses, it would have been natural for senior executives like James Murdoch to take a thorough look at reporting practices going back years. Officially, that didn't happen. In his letter announcing the closure of NotW last week, he implied that information was kept from him and also spoke of News International having failed "to get to the bottom of repeated wrongdoing that occurred without conscience or legitimate purpose" – without explaining why this was. The younger Murdoch took over as chairman of News Corporation's assets in Europe in 2007.

On the payment to victims of phone hacking, which one would assume was a red flag for Murdoch, he wrote: "The company paid out-of-court settlements approved by me. I now know that I did not have a complete picture when I did so. This was wrong and is a matter of serious regret."

Why he didn't have a "complete picture" while paying what amounted to hush money (the payment came with nondisclosure requirements) is unclear. Did Crone fail to tell him something, or perhaps Myler? At any rate, Myler and Crone are now out a job, while James Murdoch soldiers on. His scheduled appearance at Parliament next week should be fascinating.